Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China.
PLoS One. 2012;7(8):e44122. doi: 10.1371/journal.pone.0044122. Epub 2012 Aug 31.
Ammonia oxidation is performed by both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). To explore the effect of ammonia concentration on the population dynamic changes of ammonia-oxidizing microorganisms, we examined changes in the abundance and community composition of AOA and AOB in different layers. Most of the archaeal amoA sequences were Nitrosotalea-related and the proportion that Nitrosotalea cluster occupied decreased in the surface layer and increased in the deep layer during the cultivation process. Nitrosopumilus-related sequences were only detected in the deep layer in the first stage and disappeared later. Both phylogenetic and quantitative analysis showed that there were increased Nitrosomonas-related sequences appeared in the surface layer where the ammonia concentration was the highest. Both AOA and AOB OTU numbers in different layers decreased under selective pressure and then recovered. The potential nitrification rates were 25.06 µg · N · L(-1) · g(-1) dry soil · h(-1) in the mid layer which was higher than the other two layers. In general, obvious population dynamic changes were found for both AOA and AOB under the selective pressure of exogenous ammonia and the changes were different in three layers of the soil column.
氨氧化由氨氧化细菌（AOB）和氨氧化古菌（AOA）共同完成。为了探究氨浓度对外源氨选择压力下氨氧化微生物种群动态变化的影响，我们检测了不同土层中氨氧化微生物的丰度和群落组成的变化。大多数古菌 amoA 序列与硝化螺旋菌属（Nitrosotalea）相关，在培养过程中，Nitrosotalea 菌属的比例在表层减少，在深层增加。在第一阶段仅在深层检测到与硝化刺菌属（Nitrosopumilus）相关的序列，随后消失。系统发育和定量分析均表明，在氨浓度最高的表层出现了更多与亚硝化单胞菌属（Nitrosomonas）相关的序列。在选择性压力下，不同土层中的 AOA 和 AOB OTU 数量减少，然后恢复。中层的潜在硝化速率为 25.06 µg·N·L(-1)·g(-1)干土·h(-1)，高于其他两层。总的来说，在外源氨的选择压力下，AOA 和 AOB 均出现明显的种群动态变化，且在土壤柱的三个土层中变化不同。
